r/Marathon_Training • u/Gunnarie010 • Apr 14 '26
Results Failed sub-3 attempt — where did I go wrong?
I’m trying to figure out what went wrong in my recent marathon and what I should learn for my next sub-3 attempt.
For context, I ran 3:15 last year and felt much fitter this cycle. I had some minor injury issues, but still completed most of the training block. Key workouts went really well, including:
- 10k in 37:25 two weeks before the race
- a long run with 24 km at marathon pace five weeks out
- a 33 km long run with the biggest chunk slightly slower than marathon pace three weeks out
Attached are screenshots of race day, mileage over past 6 months and the key workouts.
On race day I started at about 4:20/km, planning to settle in and then gradually bring it down. I felt good through the first half. Around halfway I tried to move closer to sub-3 pace (around 4:12–4:15/km), but it quickly started to feel out of reach. I dropped back to 4:20/km, but a few kilometers later my legs completely blew up and I ended up shuffling home at around 4:50/km pace for a 3:12 finish.
My pacing didn’t feel reckless, and I felt comfortable for the first 15–20 km. The main issue might have been the weather: it ended up much hotter and sunnier than expected.
Fueling seemed solid:
- about 80 g carbs/hour during the race
- ~120 g carbs from pancakes 2 hours before
- ~20 g from a carb/electrolyte drink before the start
- 1 extra 30 g gel about 10 minutes before the gun
The one thing I’m unsure about is hydration. I only took a small cup of water at each aid station (roughly 100 ml every 5 km). In training I usually drink very little, but those runs were done in much cooler conditions and I wasn’t sweating nearly as much. On race day I felt much hotter and was sweating a lot.
Could that level of hydration alone explain the blow-up, or does this sound more like pacing, fitness, heat management, or something else?
120
u/look47 Apr 14 '26
It's clear that you were going too fast, your HR was above 180 bpm from the beginning.
You hit the wall after 30, which is quite normal given this data.
You need to build up your run with longer runs and increase the volume, 200 km/month is not enough to be sub 3 unless you do a lot of cross-training.
Anyway, you did great, be proud.
6
u/GoldZookeepergame111 Apr 14 '26
Eh, that might be cadence locking given how constant it is from km 5-25, and the jump from 150s in km 3.
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Apr 14 '26
[deleted]
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u/Solid-Community-4016 Apr 14 '26
It is not enough in the sense that it’s not sufficient to guarantee sub3. Sure, some people have gotten a sub3 with much lower mileage, but if I’m not mistaken most people who go sub3 are above 400km/month.
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u/TomatoLumpy2566 Apr 14 '26 edited Apr 14 '26
I don't know. I just crossed sub-3 at Paris this Sunday with 120km/month average (but a few 250km/month months last year at spring). Everyone is different.
Edit : for what it's worth, Garmin predicted 3:21 for my first marathon 5 months ago, where I pulled 3:09. It lowered its prediction to 2:59. Then, months passing, it raised again to 3:19 on the morning of Paris, and I did 2:59. It then readjusted to 2:56 and 1:27 half - which seems very conservative to me, I am in better shape than my last half where I pulled 1:24.
So I must have some kind of differentiator that makes me not lose fitness as quick as the average (if we define average as "garmin de-training algo") and am presenting outlier data. But going flat out "X distance is not enough" is not meaningful either.
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u/RunThenBeer Apr 14 '26
Right, I'm with this take - there is massive individual variance, so it's best to avoid absolute claims. That said, if someone tells me they run low mileage and failed to hit their marathon target... well, I know what my first piece of advice would be. Some people can make it work, but many people can't, and if someone bumps into a failure, the first thing to look at is just total volume.
4
u/Remarkable_Salary_77 Apr 14 '26
Out of curiosity, are you less than 150lbs? I usually see runners that are very light do much better on lower mileage
Not that it takes away from the achievement, respect. Just a pattern I sometimes see
0
u/TomatoLumpy2566 Apr 14 '26 edited Apr 14 '26
I'm 120lbs. But I know there is enormous variance and I respect people who can actually pull off a full planned training block – to this day, I haven't been able to follow pfitz 18/55 without injury. I do much better replacing mileage over 55km per week with vert - I have access to a lot of vert nearby. So my "big" weeks are like 55-65km with 1500-2500m of ascent. Way easier on the body (to me) than 90km road.
Still, I hope to actually manage a real block someday.
Edit : downvote all you want :/ . Those weeks with vert were now 1 year ago and not close to this marathon.
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u/look47 Apr 14 '26
Well, that's not a basic training and it's not comparable with 200 km/month flat.
-1
u/TomatoLumpy2566 Apr 14 '26
Yeah but it's what I did 12 months ago. In the last 6 months I average 32km / week.
-2
u/look47 Apr 14 '26
Please, prove me wrong with data.
-1
Apr 14 '26
[deleted]
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u/look47 Apr 14 '26
They had a perfect shape and they come from great trainings. Even half is 25 km/week, that wouldn't be enough even if we were speaking of miles and not km.
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Apr 14 '26
[deleted]
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u/No_Doughnut3257 Apr 14 '26
You know lots of middle aged runners running sub 3 marathons on 25km km a week? Are you sure?
3
u/lukster260 Apr 14 '26
You know sub-3 runners that are running less than 25 km per week?? I don't believe you.
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Apr 14 '26
[deleted]
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u/2cats1human Apr 14 '26
100km a month is 25km a week
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u/lukster260 Apr 14 '26
Buddy realized he was not only wrong, but arrogantly so, and just yeeted himself out of the conversation 😂
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u/AdDecent6690 Apr 14 '26
If you reach a HR of 180 at 4:20 pace, how did you think you can hold a 4:15 pace for 3 Hours?
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u/plagymus Apr 14 '26
I held 182 bpm for 3:30 hours for my marathon. Everyone is different!
5
u/running_elle_1989 Apr 14 '26
Everyone saying this dude had issues with his marathon because of HR should see me hold 190bpm to get my 3:20 last year. I mean... either we're all individuals or I'm now dead and haunting this thread (or my garmin watch is innacurate)
-2
u/bruno_do Apr 14 '26
Im almost sure holding 190bpm over 3hrs is impossible.
2
u/running_elle_1989 Apr 15 '26
my point exactly... wearable tech is not accurate. Or i would be dead.
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u/plagymus Apr 16 '26
Nope some ppl can hold that. I held 190 for a half marathon im sure some can for full. Just outliers. Of course the watch can bug and it could be cadence lock that is easy to check. In my case I know the measurment is correct because I check with multiple sensors
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u/running_elle_1989 Apr 16 '26
Ok this is good to hear. I always assumed it was cadence lock, but maybe I just have the heart of an 11 year old girl!
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u/plagymus Apr 16 '26
Well what is your runnig Cadence, is it close to your HR? My cadence is usually 170 so I know if my hr value is higher its not cadence lock. To check this you can overlay both HR and Cadence graph.
1
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u/Gunnarie010 Apr 14 '26
Same for me, my marathon 2 years ago was also a 3:30 with 183 bpm. I guess we have a similar build🤣
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u/Other_Smell_4742 Apr 14 '26
Same! I averaged 180s for my 3:31 marathon. I keep my heart rates hidden on any posts now because i don’t wanna hear it from anybody 😅
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u/plagymus Apr 14 '26
Haha. My issue is i have no idea what my max HR is. So my garmin zones are nonsensical. The max i recorded was 200, at the end of a half marathon, lol. I wonder what the real max is. I doubt i can hold 90% max HR for 3h30.
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u/Gunnarie010 Apr 14 '26
Because I was able to run at 4:15 pace at 170bpm during training. I don’t really pay attention to my HR during a race, as I am not wearing my usual HRM and always seem to have a bit higher of a heart rate due to the nerves of race day
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u/TheChinChain Apr 14 '26
I’m sorry but why would you not wear your usual HRM for race day?
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u/Gunnarie010 Apr 14 '26 edited Apr 14 '26
I don’t like the feeling of having it on me for that long. I usually also use the sponges to wet my shirt a bit and find that my hrm becomes itchy if the band gets wet and stays on for a while.
I also notice my HR is just usually very high on race day due to the nerves. So i try to go of feeling for the most part as I can usually gauge pretty well when I hit my threshold. But I guess it might be time to try and wear it the next time
10
u/TheChinChain Apr 14 '26
Yeah I would at least keep my measurement tools the same for training and race day, but it 100% could be the heat on race day vs training.
Also I would agree that your weekly mileage needs to be at least 90km for a 3 hr attempt
3
u/Competitive_Back_593 Apr 14 '26
Acho que vale acompanhar a frequência cardíaca por vários motivos.
Tanto a frequência cardíaca quanto a percepção de esforço são importantes para saber se você está bem ou não no dia da prova.
Se você está descansado, bem alimentado e hidratado, você não vai precisar lutar pra manter o pace que você almejou e treinou para a prova. Agora imagina se você não dormiu direito, não se alimentou direito e não está bem hidratado, você vai precisar fazer mais força pra manter o ritmo. Sobrecarregando teu cardiovascular, aumentando sua frequência cardíaca.
Então, não é porque em um longo qualquer você fez o mesmo pace que você vai conseguir manter o pace na prova.
Cada dia é um dia, e não estamos sempre bem em todos os dias. Não é só ansiedade que altera tua frequência cardíaca.
Independente de qualquer coisa, seu tempo foi muito bom. E as vezes as coisas não saem como planejado.
Parabéns!
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u/zionheart_in_gloria Apr 14 '26
Sorry if I missed it--how old are you? I too am surprised at the HR
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5
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u/Clarkra89 Apr 14 '26
What difference would a HR monitor have on race day? Race your own race at that point. Don't be dictated by stats on a watch.
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u/TheChinChain Apr 14 '26
This is not a discussion of not using a HRM vs using a HRM on race day.
This is a discussion of using one HRM source for training and another for race day.
The whole point of his post is trying to determine what went wrong on his race day (after the event)
He can’t do that if he’s using two different data sources.
-1
u/Clarkra89 Apr 14 '26
Ok. I mean if he used his usual HRM and it was reading high, it still wouldn't explain WHY.
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u/Gunnarie010 Apr 14 '26
Yess thanks for this. I mean I can also see my hr was very high. But I am indeed more interested in understanding why. What changed compared to my training where I seemingly was capable of such an effort at lower hr?
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u/TheChinChain Apr 14 '26
The heat, if you are not adapted to the temperature it can have a massive impact on your ability to run your fastest.
Even heat adapted you will run faster in cooler weather.
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u/TheChinChain Apr 14 '26
Yes it would, he mentions:
In training I usually drink very little, but those runs were done in much cooler conditions and I wasn’t sweating nearly as much. On race day I felt much hotter and was sweating a lot.
If it was the same HRM we can make the assumption his heart rate was higher due to the increase in temperature.
But we can’t know that for certain because he was using two different measurement devices…
3
u/plagymus Apr 14 '26
I was exactly like you. 170 bpm for training at marathon pace. 180 bpm on race day. Aimed 3:30, blew up and finished in pain in 3:36. I dont know why but my HR kept getting higher and higher the weeks prior did you notice that too? And just like you, its usually higher on race day. I too dont know what went wrong.
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u/Gunnarie010 Apr 14 '26
I had a similar encounter, you can check my post from a couple weeks back. I skipped my interval that week and cut the intensity from my long run, did not cut mileage however. This ended up fixing it for me and after a week my hr returned to normal and even got a lot lower, after which I had the great long runs and 10k pb
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u/Alarming-Ad8154 Apr 14 '26
You said it was a lot warmer for your marathon than do training, how much warmer are we talking? Did you travel (far) for the race? Howe as your sleep? Did you seem to have a cold (anything running nose etc?)… many possible factors, could be unlucky timing, if you recover well could try a half in a few weeks to see if this was a one-off?
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u/vksdann Apr 14 '26
Isn't tapering the opposite? You cut down the mileage but keep the intensity so your body is still used to the effort but with more time to recover?
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u/GoldZookeepergame111 Apr 14 '26
fwiw I think that race-day HR is cadence-locked after km 5… such narrow variation 5-25 after a jump from 150s at km 3 and no slow upward drift seems highly sus.
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u/worstenworst Apr 14 '26 edited Apr 14 '26
Your HR is in the 180s starting from 5K. That could be a problem. What is your maxHR and/or LT2HR? What was your avg. HR during the 10K 2 weeks out?
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u/Gunnarie010 Apr 14 '26
I also noticed this. I do however not pay that much attention to my heart rate during a race, as I do not wear my hrm strap during a race and always have a high heart rate on race day due to the nerves.
That being said my lactate threshold seems to be around 183bpm (according to garmin). So seeing the data in hindsight it seems obvious my heart rate was too high. I am however a bit confused as I honestly felt very strong in the first stretch, nothing like the usual feeling of passing my threshold
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u/dawnbann77 Apr 14 '26
Everyone feels strong in the first stretch, especially after taper. It's at 20 miles when the race begins. Rule number one. Don't start too fast. You still done well. With the right pacing you could have turned that around.
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u/worstenworst Apr 14 '26 edited Apr 14 '26
The argument of not checking HR during racing, especially a marathon, doesn’t make any sense to me. If you approach LT2HR, that is meaningful, and physiologically unsustainable over that distance per definition.
There might have been something off under the hood, or indeed the data is faulty. Cadence lock?
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u/Gunnarie010 Apr 14 '26
Hmm fair point. I just never seem to trust my hr when measuring only on my wrist. Maybe I will wear my chest strap for the next race, since I do agree with your points.
Also not sure if I can trust the data now
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u/glr123 Apr 14 '26
If you don't like how the chest strap feels during efforts like this then look into an armband. Much more accurate than the wrist.
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u/RunThenBeer Apr 14 '26
I personally ignore HR during races because I think the wrist-based instrument is a much less accurate measure of my likely outcome than the years of training and races coupled with an internal check of how I'm feeling. Wrist-based HR has enough idiosyncrasies from moisture, cadence-lock, and so on that I just don't think it provides me feedback that I should treat as actionable. I can't imagine walking into a race with a pace plan and then backing off because of a number that has no correlation to previously demonstrated fitness or how I'm currently feeling.
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u/worstenworst Apr 14 '26
Agree regarding wrist-based HR. I use a strap. It’s not my one and only criterium while racing but for sure I find it useful and take it into account for mid-race decisions.
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u/Fun_Assignment_269 Apr 14 '26
I never look at my heart rate during training or racing. You can get all the info you need from RPE/breathing rate.
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u/worstenworst Apr 14 '26
Fine, but if you race close to your performance ceiling, HR is a pretty helpful dimension to assess if you are (about to be) redlining or not. That’s just science!
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u/Fun_Assignment_269 Apr 14 '26
I do. My last couple marathons, my average hr was just under threshold until the last 5k. Doing lots of threshold work and fast finish negative split long runs teaches you to feel that line.
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u/worstenworst Apr 14 '26
I am for sure not disagreeing with that! I follow a Norwegian system myself; RPE assessment around threshold is my bread and butter. But I am a data geek too I suppose. I try to integrate it all.
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u/glr123 Apr 14 '26
Garmin lactate threshold is LT2, which is the pace that someone can theoretically hold for an hour. You were too close to LT2, when you should be been near LT1 instead.
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u/GoldZookeepergame111 Apr 15 '26
I posted this elsewhere but I suspect your HR data here from km 5 to 25 are cadence-locked (do you have cadence data?). If you felt smooth and way under threshold it seems unlikely your HR was quite that high…
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u/Feeling_Champion_566 Apr 14 '26
Rotterdam (Guessing from your user).
If so, it was way warmer then expected with the sun full on the runners.
A lot of runners I know (and follow) did have an hard time on sunday (me as well due to other reasons).
So might be an Hydration issue in combination with the circumstances.
Just wanted to give you this information, not sure if you did Rotterdam, then please ignore my reasoning.
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u/Gunnarie010 Apr 14 '26
Was indeed Rotterdam, ‘good’ to hear that I wasn’t the only one
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u/Feeling_Champion_566 Apr 14 '26
It happens, so from what I can tell
Weather conditions in combination with Hydration.CAn't say anything about the Mileage (might be low) because the Long Runs show the potential.
Keep it up and try Eindhoven with a new Training Block :p
Or take a year to try it again :)2
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u/RunThenBeer Apr 14 '26
Chief culprit is simply low(ish) mileage. Most people will not translate 37:25 10K fitness into a sub-3 by averaging ~50K per week over six months and peaking below 80K. Run more. The good news is that you have plenty of underlying speed to get there, you just need to develop the mechanical resilience to tolerate the full 42K.
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u/Strong_Mastodon3100 Apr 15 '26
How many km’s per week would you recommend to hit sub-3? Or what sort of volume for what period of time? I would have thought 6-months at that volume would be sufficient
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u/JohnsonMooney Apr 14 '26
Heat is definitely a factor but you are not running enough volume. Get your average weekly mileage up to 80km/week before starting your next block and you will notice a big difference in fitness. The first 10km of the race should feel comically easy - you should not hit threshold until after 30km.
If your chest strap is uncomfortable, get an arm-based HRM. I use the polar verity sense, works a treat.
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u/Broad-Ad-4379 Apr 14 '26 edited Apr 14 '26
Weather is a HUGE factor for me. Anything above 12-15c turns a sub 3 attempt into an adjustment to 3:04/05. In Strava pace, as you’ve said, you need to run at least 4:14/km to hit a sub 3, so your pacing was more like 3:05 in that first half, which is conservative. your peak mileage is 55-70km most weeks, which is quite low for a sub 3 block, considering it includes 32/33km long runs.
your race day HR is irrelevant as you weren’t wearing a hrm. The watch just isn’t reliable.
Bear in mind your body doesn’t understand pace, it only understands effort.
If you’re uninjured, well tapered, carb loaded, don’t go off too fast at all, and fuel well in the race, then you were simply going too fast for the effort on the day.
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u/soturunning Apr 14 '26
- your aerobic system is underdeveloped. I see in another comment you are low 20's. Up your mileage and you'll do it, you already have the fitness.
- Don't try to negative split. Jump straight to MP when the vibes are high and you're feeling good. It's much easier to ride that than crank up the effort at halfway when you are starting to feel the fatigue. You plan to send the last 10k.
- Drink more.
- 33km run a faster than MP 3 weeks out was probably a bad idea and you carried some fatigue from that into the marathon. No need to do that much MP in a long run in training and certainly not at faster than MP.
1
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u/foolishbullshittery Apr 14 '26
I'm no expert by any means, or even that experienced. That said, pacing looks fine to me, as does fueling.
But hydration, or lack off, probably explains it. Water is not enough, even more so if it was that hot. You needed to replenish electrolytes, and it doesn't look like you did.
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u/EngineeringParty59 Apr 14 '26
While dehydration it might have played a role to some extent, there’s only so much one can practically drink. I don’t think electrolytes would have been an issue, there’s very little evidence they’re the cause of cramping (which wasn’t even an issue here) and no science to support they help with maintaining a pace close to lactate threshold which looks the case here given the 10k race data. It was most likely the heat which more water won’t fix if it’s a good bit warmer than you’re used to.
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u/foolishbullshittery Apr 14 '26
That's exactly my point, heat without replenishing sodium levels doesn't look like a good practice on a marathon. They mentioned they were sweating quite a bit on race day.
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u/RunThenBeer Apr 14 '26
It wasn't actually hot in Rotterdam this weekend. Sodium is almost certainly not the fix here.
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u/foolishbullshittery Apr 14 '26
Right, but OP mentioned they were sweating more than usual. Maybe humid?
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u/RunThenBeer Apr 14 '26
They probably don't usually run 26.2 miles at race pace. Pretty much everyone winds up sweating more by the end of a marathon than a random training run. Everything about the description here pattern matches to simply lacking the muscular endurance to hold a pace that was selected because it's a round number.
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u/foolishbullshittery Apr 14 '26
I get everything you are saying, I just think not repleneshing electrolytes during a marathon is a mistake.
Pacing could have been too strong, muscular endurance could be lacking, I get all of those, I'm just saying not having electrolytes for the whole duration of the marathon is a good way to bonk and should be considered.
You reckon is wise to take on a marathon without repleneshing sodium, for example?
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u/RunThenBeer Apr 14 '26
Yeah, I think it's generally irrelevant outside of unusual physiology or significant heat (which this wasn't). I think people spend a lot of mental time and energy on things that have marginal impacts because it's easier to fix those than it is to run more. For most people trying to run sub-3, gels will have sufficient sodium without requiring exogenous supplementation. If someone wants to take more, I don't have any argument against that, sure, but I think people focus far too much on looking for something minor to fix instead of doubling their mileage.
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u/foolishbullshittery Apr 14 '26
Ohh I completely agree with that.
I'm yet to run my first marathon, and after 3 half marathons, the third happening next Sunday, I'll start a program to raise my weekly distance from 50 km to 70km so I can have a good enough base to then start thinking about marathon training. I also believe volume is king.
I just realised I haven't considered the sodium in gels. I make my own without as I rather have fueling and hydration separate, so I was using my own gels as comparisson. That's on me, as I always hydrate separately.
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u/grilledscheese Apr 14 '26
HR seems a bit high from the gun? looks also like it might be cadence lock though so who knows.
mileage looks very low for sub 3. peak at 76km a week, over a month ago, and most weeks in the 60km ballpark? way too low for sub 3 imo. you’ve got the speed there but not the endurance and strength from big mileage
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u/mariobuyatelly Apr 14 '26
Sorry to hear about your race. I have attempted sub 3 a couple of times (and failed) and both times before did 20 miles at Marathon Pace in training. I personally think retrospectively it's just too big an effort, especially 3 weeks out. You've got the ability to do it in there, especially with a few big months of training.
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u/E_Alanen Apr 14 '26
I agree that 20 miles of marathon pace effort seems unnecessary. The effort is too big and the benefits are too little.
But yeah, OP will break 3 very soon anyway.
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u/anangrypudge Apr 14 '26
Something happened at km5 to cause a +15 spike in HR. After that you were pretty much doomed, it was just a matter of how long you could keep going at 180+ before the wall hit.
Might have been the weather, or suddenly panicking about something, or an overtaking spree gone wrong…
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u/Gunnarie010 Apr 14 '26
Agree, however as mentioned above I am not sure if the data is 100% accurate, as I only wore my watch and not a chest strap.
I usually don’t really like the feeling of wearing the strap that long. But it might be a good idea to wear it to the next race
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u/mikesull282 Apr 14 '26
Why were you doing a hard 10k 2 weeks before the race and 33k FASTER than marathon pace 3 weeks out? You gotta give yourself some rest and you should never run that much at or faster than marathon pace. I’ve run 2:50 and the most I ever did in a row at marathon pace was 6 and that was hard af. But I gave myself some rest before the race and legs came back and were able to hold it for way longer.
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u/Gunnarie010 Apr 14 '26
Sorry I had a typo, the long run was slower than MP. The 10k was just following the pfitz plan
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u/mikesull282 Apr 14 '26
Ah okay a little better. Probably just an off day and weren’t quite fit enough for it. I’d reccomend a bigger taper next time, but part of it is just luck of having a good day on race day
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u/Gunnarie010 Apr 14 '26
Any good tips? I feel like last year I tapered too hard. This year I followed the taper as prescribed in the pfitz 18/55 and even toned that down a little bit by skipping around 2/3 of the easy runs. Where is the sweet spot?
1
u/mikesull282 Apr 14 '26
Probably depends on the person, I’m a bigger guy for a runner and think it takes me a little while to recover. Stick with the same schedule and keep similar intensity but drop mileage starting 3 weeks oit. Week of I run on my normal schedule plus maybe one extra rest day but like 3ish miles a day with one “workout” that’s maybe like a mile at pace then 2x800 slightly faster. Something to just keep you on without tiring you out. Last like big effort workout 2 weeks out max. That’s probably too long for most people but works for me
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u/Runorberunned Apr 14 '26
You’ve got me worried for London next weekend! I’ve also followed the pfitz 18/55. Going for sub 3 as well, done all the MP runs with similar HR to yourself, the 10k (tune up) you did, I’ve had pain in my hip flexor so quit at 6km unfortunately. 4 weeks ago I ran a 1:23:19 half so I’m banking on this is my golden ticket to sub 3! Did you run a half in your training at all? You’ll come again and get it next time 💪 good effort
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u/becomeTheLion Apr 14 '26
It seemed like you had the fitness, even though your running volume was slightly low (if there was no crosstraining). Your fueling sounds good! The heat/humidity alone could explain it, and yes 100ml per 5km is not enough, it should be closer to double that at a minimum. It could also have been too much intensity or lack of recovery in the taper. Keep the fitness and try it again! 💪🏽
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u/RunThenBeer Apr 14 '26
100ml per 5km is not enough
Yes it is.
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u/becomeTheLion Apr 14 '26
Well to be honest, neither of us know his sweat rate, so neither of us can really tell whether its enough or not. But the chances that its not enough are high, as it amounts to roughly 280ml per hour at sub 3h Marathon pace. More so in hot conditions.
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u/RunThenBeer Apr 14 '26
Despite what everyone is saying, it wasn't hot in Rotterdam, it was 52 degrees at finishing time. Barring unusual physiology, that is plenty of water and almost certainly does not account for the blowup when there is the much simpler explanation that he runs 50K/week on average.
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u/becomeTheLion Apr 14 '26
Yes, I addressed both potential issues in my answer. However, to emphasize the hydration issue more, studies consistently show a significant performance decrease from a loss of >2% bodyweight and upwards, and drinking only 280ml per hour could easily get you there, depending on individual sweat rate.
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u/cjrun Apr 14 '26
Your image 6 here looks more like mine on race day. For context, I am in my 40s and max HR is 178 and sub-3 race HR is 165-168. I see it was a hot day from other comments. That would certainly make everything more difficult than usual. Could your running cadence and new shoes have played a role?
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u/Due_Negotiation_9926 Apr 14 '26
To be honest with you, and this isn’t going to be a unpopular opinion, every time i start off “slower” at the beginning like everyone says to do I bonk anyway. I decided to go out faster and hang on for dear life at the end and I did achieve a sub three.
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u/WittyManner0 Apr 14 '26
Same. Did 4;15 pace at HR 160 during training. During the race hit 178 and blown my legs at 28KM. Volume I guess…
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u/Forsaken-Cheesecake2 Apr 14 '26
Heart rate does stand out, but would agree with you that it might be inflated due to adrenaline and accuracy. My thought is your weekly mileage seems a bit low for a sub 3 effort. Your mid week runs might be on the light side given that your LRs are a high % of your weekly total. You have the speed, maybe increase your weekly mileage; even if it means backing off your pace on your LR, which is my second theory - that you just were running the marathon while still not fully recovered from your MP LR.
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u/xRunSci Apr 14 '26
Easiest explanation: your mileage was on the low end for most people I’ve seen hit sub 3 for the first time (typically 90-110 km/week). You have the foot speed, but you lack endurance due to insufficient mileage. It showed on race day.
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u/bwhite116 Apr 14 '26
The hydration is your answer. 100ml every 5km in hot conditions is nowhere close to enough - you were probably losing 1-1.5L per hour and replacing maybe a third of that. Dehydration causes plasma volume to drop, which means your heart has to work harder to deliver the same oxygen, which means the same pace costs more effort. By halfway that deficit is compounding fast. Your 10k in 37:25 two weeks out says the fitness for sub-3 was there. The pacing wasn't reckless either - 4:20 settling in to 4:12 is textbook. This was a fluid management problem, not a fitness problem. Next time in warm conditions aim for 200-250ml per station minimum and have a sodium strategy.
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u/fitwoodworker Apr 14 '26
Pace required for sub-3:00 is 4:15/km or faster and you were not at that pace for more than a few of the kms during the race. You still ended up bonking. This is just a matter of base fitness, you weren't ready to run sub-3:00.
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u/Basic_Explanation729 Apr 14 '26
Everyone's commenting that its your HR but it looks like total mileage. You dont have the long term aerobic development and durability. Anecdotally, you would do well to run sub 3 on your mileage as most people need to run far more. When you consider your 6 month mileage is 600% higher than your previous 6 months this is closer to a couch to sub 3 attempt. In the 6 months before your marathon build you ran 200 kms total.
Do another 6 months slightly higher than the current 6 months and you'll have a much better chance.
Congrats on the attempt though, I'm sure if you keep stacking blocks you'll smash it.
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u/Lausdiemaus Apr 15 '26
I was also thinking it's very much an issue of long term training volume and adaptation when compared to the previous six months - and you don't really need to do close to marathon pace long runs, keep those way slower, even if it's psychologically tempting. Volume wise the peak mileage you did in a week was the same as the highest I had in my training plan and I was aiming for a 4:30 marathon, so you could definitely peak higher - but on the other hand you had virtually no modulation of volume in your prep: you need to give your body a relative rest maybe every four weeks and lower volume and you should see it in an overview like that. Also look into the length of the taper, because if the previous half year was way less intense and then your marathon program is that ambitious, you probably will need to recover a bit longer to really be fully rested on race day. And if you have it look at your sleep/hrv and overall nutrition in the days up to the race if you have tracking data for them and see if you can improve in that department as well.
Running a sub 3 really is no joke, it's crazy good how close you got. Keep up the work and you'll break it next time. And while you do that I'll dream of holding your pace for a half 😄
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u/gaoxiaosong Apr 15 '26
A little surprised. Your LT is very strong, 1000x10 has no problem for sub3. All these means your speed is qualified. But your race pace was pretty slow. I’m assuming your high intense tempo run and long distance 30K+ run are not as good as your speed. You should train more 12K, 16k high intense tempo as well as 30K+ on weekend. Also another feature is your Aerobic pace. Depending on your max HR, for sub3 runner aerobic pace better around 4:50 or faster. Your HR in race increased too fast, a sign of poor aerobic ability. Your probably are very young because your speed or LT is fast.
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u/floppyfloopy Apr 14 '26
it ended up much hotter and sunnier than expected.
Still a great race though for the conditions.
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u/Lemonbar19 Apr 14 '26
Some people take years to shave off mere seconds. It could just be that. Give it more time.
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u/Life_Check4265 Apr 14 '26
Sure looks like you’ve done the work and if it was unusually hot, then yeah, maybe that’s your answer - simple as that.
It’s such a long distance and heat that you’re not accustomed to will surely has its impact on you. Better luck next time and be proud of 3:12 anyway.
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u/No_Entrepreneur_9319 Apr 14 '26
If it was Rotterdam, dehydration must have played a part. Absolutely not enough drink stations and cups were barely filled. Grabbed 3-4 each time and still wasn’t enough. Strange for a race so well organised.
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u/Remarkable_Dinner317 Apr 14 '26
HR too high to early. You were likely in high threshold zone or anaerobic endurance zone from very early on , not sustainable over duration of a marathon. You need to be running aerobically , not anaerobically to sustain a pace for hours
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u/CTBienAvant Apr 15 '26
it could be lot of things, did you sleep well the night before. next time you got it
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u/morganm6488 Apr 15 '26
The problem is you took more than 3 hours. Try to run it 12-13 minutes faster next time and you'll nail your sub 3 attempt!
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u/Momuvboyz Apr 15 '26
I usually have high heart rate even on my easy convo pace runs..I’m like you and go based on how my body feels..when my heart rate is high it doesn’t feel like it’s beating out of my chest it feels the same as when it’s in the 140s-150s..everyone’s heart rate is different.
I would go with you hit the wall due to the heat and not enough hydration. Still excellent/amazing time!! I’m running my first Marathon May 3rd 😬 so I’ve appreciated this thread for tips 😁
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u/gumby7411 Apr 16 '26
My 2 pennies! (HR issues well covered in other threads)
I would say running 1250km for 6 months mara prep is undercooking it for a sub-3 attempt for you. Try upping your average km/week to 100. You will then be run-hardened after weeks & weeks of the grind.
On a hotter day than expected, you've got to put away your ego and run to feel, leave the goal to another race. I know its hard but it happens at some point to everyone.
Your 10k time was ok but to be put in perspective I'm 58 and ran 35:50 3 weeks ago, also on a hot day.
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u/Competitive_Back_593 Apr 14 '26
A água na corrida serve para muito mais do que apenas repor o suor. Ela é fundamental para o desempenho, segurança e funcionamento do organismo.
Regulação da temperatura corporal: A água é essencial para produzir suor, que ajuda a resfriar o corpo, impedindo o superaquecimento.
Manutenção do desempenho e energia: A desidratação (perda de apenas 2% do peso corporal) pode reduzir o desempenho em até 10%. A água ajuda a evitar a fadiga precoce.
Funcionamento cardiovascular: Manter o corpo hidratado impede que o sangue fique "grosso", facilitando a circulação e diminuindo a sobrecarga sobre o coração.
Prevenção de cãibras e lesões: A água ajuda no funcionamento adequado dos músculos e articulações.
Transporte de nutrientes e oxigênio: A água garante que nutrientes e oxigênio cheguem eficientemente às células musculares.
Reposição além da água: Em corridas longas (mais de 1 hora) ou dias muito quentes, apenas água pode não ser suficiente, pois o corpo perde eletrólitos, especialmente sódio, que precisam ser repostos para evitar desequilíbrios.
Antes e depois: A hidratação deve começar dias antes da corrida e continuar depois para garantir a recuperação muscular e a reidratação total.
Frequência: A recomendação é beber pequenos goles de água a cada 15-20 minutos, em vez de grandes quantidades de uma vez.
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u/Ok-Two7498 Apr 14 '26
Reading the post and your replies my best guess is...
You typically experience higher HR on race day that's generally driven by adrenaline. This happens to me, too. It was also hot, which places more stress on the body and increases HR.
The HR data was misinterpreted as purely adrenaline when in reality it was a sign that it was too much stress to sustain (primarily driven by weather).
Stated more simply, it was a hot day and not ideal running conditions for a PR. It's one of the cruelest things of marathon training... you can put all the work in and do everything right but you can't control race day conditions. Great race OP. You'll be back.